1. Field of the Invention
The present invention relates generally to the field of electronic component heat dissipation. More particularly, this invention relates to an improved heat spreader for use with heat-emitting electronic components.
2. Description of the Relevant Art
Heat sinks are commonly attached to electronic components to facilitate heat dissipation from the components. A heat sink is typically composed of a thermally conductive material, such as aluminum, with a plurality of fins or pins on its exposed side. Heat is dissipated from the fins or pins to the surrounding air principally by thermal convection.
Some heat sinks are mounted to, incorporate, or include a thermally conductive element that facilitates distribution of heat from the surface of the component to the heat sink. The intermediary thermally conductive element may be referred to as a “heat spreader.” U.S. Pat. No. 5,969,949 issued to Kim et al. discloses a heat spreader slug interposed between an electronic component and a heat sink having a plurality of fins.
Heat sinks may be coupled to a component by a variety of means known to those skilled in the art. For example, the heat sink may be coupled to the component by an adhesive or by various types of retainers such as clamps, brackets, or screws. U.S. Pat. No. 5,615,735 issued to Yoshida et al. discloses an apparatus having a clamp for coupling a heat sink to an integrated circuit package. The clamp has legs that cooperate with mating features on a printed circuit board.
In many cases, the mating surfaces of the component and the heat sink do not match when conventional mounting methods, materials, and assembly practices are used. Such surfaces are referred to herein as “non-matching surfaces.” Non-matching surfaces may occur because of irregularities in the mating surfaces (such as roughness or other non-planarity), differences in the contours of the mating surfaces, or misalignment of the mating surfaces. As an example, the mating surface of a component may contain a step or ridge, while the mating surface of a heat sink does not. As another example, a fastener head may protrude slightly from an otherwise flat upper surface of a component, with no compensating feature on the heat sink. Alternatively, poor contact may result where the heat sink is not mounted directly to a component itself, but to another component such as a printed circuit board, and there is a misalignment between the mating surfaces of the component and the heat sink caused by mechanical tolerances among the several parts.
Even if the mating surfaces of a heat sink and component generally conform when the heat sink is initially installed, contact may later be lost or diminished due to loads encountered during assembly, transportation, or use of the system. For example, a heat sink may slip from its originally installed position due to vibration encountered during transportation.
Regardless of the cause, the existence of non-matching surfaces between a component and a heat sink reduces the effectiveness of the heat sink, thereby increasing the operating temperatures of the component. Higher operating temperatures are associated with decreased reliability of electronic components. Accordingly, there is a need for an apparatus and method for improving conformance between the mating surfaces of a heat sink and an electronic component.